Grinding apparatus.



H. K. HITCH'COCK. GRINDING APPARATUS. APPLICATION FILED JULY 28, 1913.

Patented Aug. 31', 1915.

4 SHEETS-SHEET I.

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FIGJ.

WITNESSES H. K. HHCHCOCK.

GRINDING APPARATUS.

APPLICATION FILED 1ULY28, 1913.

Patented Aug. 31, 19 15.

4 SHEETS-SHEET 2.

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WITNESSES h? J] INVEN TOR I fl/{WW' H. K. HITCHCOCK.

GRINDING APPARATUS.

APPLICATION FILED JULY 28. 1913 P11te11tedAug. 31, 1915.

4 SHEETSSHEET 4.

WITNESSES IN'VENTOR ffi/W a: ear

PLATE GLASS COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OFPENNSYLVANIA.

GRINDING APPARATUS.

Specification of Letters Patent.

Application filed July as, 1913. Serial m5. 131,529.

To all whom it may concern Be it known that I, HALBERT K. HITCH- COCK, acitizen of the United States, residing at Tarentum, in the county ofAllegheny and State of Pennsylvania, have invented certain new anduseful Improvementsin Grinding Apparatus, of which the following is aspecification.

The invention relates to mechanism for grinding surfaces, particularlyof plate glass. It has for. its primary objects; (1) the provision ofimproved means for adjusting the drive of the runners so that theirgreater abrading action may be directed at any portion of the sheet ofglass requiring such action; (2) the provision of improved means forsecuring the attachment of the runners to and their disengagement fromtheir supporting means, and (3) the provision of compact and eflicientmeans for regulating the pressure of the runners upon the glass beingground, the said means being constructed so as to prevent fracturing theglass due to excessive pressure being eoncentrated upon the high placesby the runners as the glass rotates there-beneath. Certain embodimentsof the invention are illustrated in the accompanying drawings,wh'erei.n'

Figure 1 is a partial section and partial side elevation showing thegeneral arrangement of the parts, Fig. 2 is an enlarged section taken onthe line II-II of Fig. 1, Fig. 2 is an enlarged detail partially insection of the bypass construction in Fig. 1, Fig. 3 is a sectionsimilar to that of Fig. 2, but taken through a modified form of construction, Figs. 4 and 5 are sections taken on the lines IV1V and V-Vrespectively of Fig. 8, Fig. 6 is a plan view of the central portion ofthe runner with the parts for supporting it removed, Fig. 7 is a partialside elevation and partial section showing the general arrangement ofanother modification of the structure, Fig. 8 is an enlarged sectionthrough the spring cylinder and parts contained therein, and Fig. 9 apartial side elevation and partial section of another modified typeofthe apparatus.

Referring first to the construction as shown in Figs. 1 andEZ; 1 is aportion of the table of the apparatus, which is rotated in the usual wayand may be of any approved type; is one of the runners; 3 is the builtupgirder or framework from which the run- Patented Aug. 31, 191.5.

ners are suspended, such girder being supported at the ends by means ofthe uprights '3 5 is the bar or post by means of which the runner 2 issuspended from the box girder or bridge 3; 6 is a plunger or pistonsupported upon the lower member of the girder 3 7 is a cylinder-orannular-chamber fitting over the plunger or piston (3 and keyed to thepost 5; 8 is a pneumatic hydraulic tank from which the cylinder 7 issupplied with fluid through the pipe 9; 10 is a handwheel by theoperation of which the engagement and disengagement of the post 5 withrespect to the runner is secured; and 11 is another handwheel by theactuation of which the rotary adjustment of the post 5 with respect tothe runner 2 is secured in order to enable the operator to shift theposition of the portion of the runner which bears hardest on the glassduring the period when the runner is being lowered and before the totalweight is applied, thus increasing. and decreasing the drive of therunner at will.

Mounted rotatably in a recess in the center of the runner 2 is thehearing and supporting block 12 around which the runner 2 rotates. Thisblock is held in position in its recess by means of the plate 13 whichoverhangs the upper edge of the block and is securedto the runner bymeans of the bolts 14 and 15. The supporting bar or post 5 isrectangular in cross section, and is provided along one side at itslower end with a projecting rib l6 fitting in a groove in the block 12.The rib is held in position in its groove by means of the key 17 havingits lower end 18 tapered, and its upper end 19 is turned laterally toreceive the screw 20 carried by the handwheel 10. The nut 22 just belowthe end 19 prevents downward movement of the key 17 with respect to thehandwheel 10. It will be seen that by operating the handwheel 10 toraise the key 17 the lower end of the key 16 withdrawn from the socketin the block 12, thus providing room to permit the post 5 to move to theright and release the rib 16 from its groove. 7

Secured to.the upper end of the post 5 is the gear 23, such gear beingheld in position with respect to the upper frame member bymeans of thenut 24', and being operable from the worm Q-Lt having driving connectionwith the shaft 25. The shaft Q-2 5 is operable from the hand' fvvheel11,' so

"i that by rotating handWheel-"thepost 5 and'th'e block be given any,de-.

sired degree of rotation. The purpose of this rotation of the post is tosecure an adjustment of the drive'of the runner 2 with respect to thetable 1. The rib 16 is off center with respect to the centerline A ofthe runner, so that the runner is eccentrically supported, and the sideof the runner farthest removed from the rib tends to drop down and bearharder on the glass when the weight of the runner is partially sup--portedon the rib 16, that is, during the starting up of the grinder. Byrotating the post 5 and changing the point of eccentric support of therunner, the runner may be made to bear heaviest upon any' desired pointof the table, thus shiftingthe driving as above described. Thedepending, sleeve sage, 28 connecting with the pipe 9. other end ofthepipe 9 is-conne'cted to the 45-- 7 gives a very rigid support for the"post adjacent the block 12, and the uprights 3 (Fig. 2) connect thehorizontal beams constituting the girder 3. I

In order to regulate the amount of pressure between the runner and theglass on the table, the plunger 6 and cylinder 7 are provided, theplunger $3 being supported upon the girders 3, and the cylinder 7 beingkeyed to the post 5 as indicated at 26(Fig. 2). Packing 27 for theplunger is provided, and fluid is admitted to the space between theplunger and cylinder through the praistank 8, and this tank, 8 issupplied with water under pressure, by means of the pipe 29 leading toan accumulator-or any other desired source of fluid pressure,'andcontrolled by a threeway hand valve (not shown). The space above thewater 30 or other liquid in thetank 8, is filled with air andconstitutes with respect to the plunger and cylinder an air spring forsecuring a resilient application of power tending to raise the post 5and the runner 2 carried thereby. A throttling valve 9 is placedin thepipe 9 (Fig; 2 and serves to regulate the resistance of the Waterflowing from thecylinder to the tank 8. A by-pass 9 is provided aroundthe valve and in this pipe is carried a check valve 9 which per: mitsthe water to flow through the by-pass to the cylinder, but preventsmovement 1n ,th'e reverse direction. The arrangement allows a freeflow'of water to the cylinder,

thus permitting the runner "to respond promptly to force tendin'g toraiseit,.while downward movement of the runner is resisted and mademorej-gradual" throttling action. of the-T'vailve 9? When it is desiredto li'ft'th into the chamber 8, reducing jithe volume of air containedtherein until-"thmipressure' of the air and water is suchthatthe'zwaterj. acting against the annular cylinder 7 raiseserun-nerfrome the table, water under pressure isadmitted ue ltothe therunner 2. When the grinding operation I 1s first started, inorder toprevent excessive breakage where the glass has a rough s'ur 7 I face,thepressure of the runner upon the glass is applied gradually, suchresult being accomplished by allowing the escape of some of the water inthe tank 8. The runner moves downward until it contacts with the surfaceof the glass, the air in the tank expanding and reducing the pressure inthe tank and cylinder, thus permitting the application of a graduallyincreasing pressure to the glass. The rate at which the increasingpressure is applied is regulated by the rate at which the water isWithdrawn from the tank 8 and can be soadjusted that the pressure on theglass isproportional to the amount of grinding accomplished during theinterval in which the increasing pressure has been applied. If desired,the flow of water from the tank'may be interrupted at anytime, therebyfixing the pressure upon the glass at a substantially constant amount,which pressure increases slightly as the runner rises, and decreases'astherunner lowers, due to the unevenness of the surface passing under therunner; Afterthe unevenness of the surface of the glass has beenremoved, the entire weight of the runher is permitted to rest upon theglass.

It will'be seen from the foregoing that the apparatusdescribed providesa very compact and easily operated meansforregulating the pressure ofthe runner upon the glass. The arrangement also tends to eliminate thefractures 'or cracks which often occur due to the momentum of the runneras it is caused to move up and down "by the uneven surface of the glassover which it tion resists any violent downward movement of the runner,as any downward movement of the runner must necessarily'cause. theexpulsion of the liquid in the cylinder above the plunger, 'andthis-expulsion ofthe' liquid is resisted by the friction of the liquidflowing through the pipe 9, and by the compressed air above the liquidint the tank 8. This resistance also increases with the extent ofdownward movement, since the air in the tank 8 is becoming more and morecompressed, and therefore moreand more resistant. It will also be seenthat the runner is free of any counterweight tending to increase themomentum ,Of the 111111131 when moved in either direction, so that themomentum of the runner in both directions is reduced to a minimum, andthe danger of fracturing correspondingly reduced. Other advantagesincident to the construction will be readily apparent to those skilledin the art.

Figs 3 to 6 illustrate a modification of the apparatus just abovedescribed. In this construction antifriction rollers 31 and balls 32 areprovided to reduce the friction between the supporting block 12 and thesocket of the table 2 in which the block is mounted. The construction ofthe post 5', the key 17, and the operating handwheel mechanism thereforis the same as heretofore described in connection with the structure ofFigs. 1-

and 2. The means for adjusting the post 5 rotarily, including the gear23' and worm 24 are the same as heretofore described, as is also themounting of the plunger 6 and cylinder 7 with respect to the girderandsupporting post 5.

The primary distinction of the apparatus of Fig. 3 over that of Figs. 1and 2 is in the relative arrangement of the plunger and cylinder, and inthe means of operation. It will be noted that in the construction ofFig. 3 a very considerable space is provided above theplunger when thecylinder is in lowered position, which is not the case in theconstruction of Figs. 1 and 2. This difference in arrangement is due tothe fact that in the construction of Fig. 3 the space above the plungeris larger and in itself constitutes an air chamber of sufficient volumeto give the resilient support, and during the operation of supporting orpartially supportingthe runner contains both air and water. The passage28 is connected directly to an accumulator or other source of liquidpressure, and this liquid supplied to the pipe 28 serves to compress theair above the plunger (5. The air spring or cushion is in thisconstruction therefore located in the cylinder insteadof in aseparatetank as in the construction of Figs. 1 and 2. It will be seenthat the apparatus issomewhat simpler and more direct in its operationthan that of' Fig. 1, and that the water supplied at the top of theplunger serves as a packing means. By proportioning the ratio of the airspace to the water space, it is possible to regulate the changes inpressure due to the movement of the runner toward and away from theglass. For instance the larger the air space the less Will be thevariation in pressure due to the oscillation of the runner up and down.The resistance secured by the plunger and cylinder arrangement of Fig. 3is also more resilient than that of the construction of Figs. 1 and 2,since there is no outflow of water through the passage '28 as is thecase in the apparatus of Figs. 1 and 2,.a part of porting bars or posts5 the constructionon the two sides of the table being precisely thesame, aside from the size of the runners, so that a description of onerunner and its supporting means will be sufficient.- The framework 3which supports the runners is of the usual type, being carried at theends by the uprights '4 and carrying the fulcrum brackets 33. Thesupporting post or bar 5 for the runner is circular in cross section andis journaled in bearings 34 and 35 carried by the frame 3 and thedownward thrust of the post is carried by the block 36 pinned to theupper end of the post. Below the block 36 is a bearing member 37 fortaking the thrust of the block 36, antifriction balls being preferablyinterposed between the two bearing surfaces. The bearing member 37 ismounted loosely for rocking movement in the end of the lever 38. A fluidpressure cylinder 39 operating the piston rod 40 hooked to the lever 38serves as.

a means for lifting the runner free from the table when it is desired tomove the table from beneath the runner after the grinding operation iscompleted. At other'times no fluid is supplied to the cylinder 39, sothat the movement of the lever 38 is not affected during the grindingoperation by the connection 40.

The means employed for regulating the pressure of the, runner upon theglass comprises the connecting rod 41, the connecting rod 42, thecylinder 43 carried by the connecting rod 42, the spring 44 in thecylinder, and the handwheel 45'provided with nut 46 engaging thethreaded portion of the connecting rod 42. The connecting rod 41 is intwo parts pivoted together at 47, and the lower portion of the rod isprovided with a head 48 engaging the lower side of the spring 44. Thecylinder is of course free of attachment to theframe, and the portion ofthe connecting rod in the cylinder slides freely through the bearingportion 49 (Fig. 8).

After the previous grinding operation is completed the runner is raisedby means of the cylinder 39 and the handwheel 45 is turned until therunner is held suspended by the reaction of the spring 44, at which timethe fluid pressure in the cylinder 39 is released. When it is desired tostart the grinding operation on the next set the hand-- wheel 45 isgradually turned allowing the .cylinder issecured rigidly to a bracket53 carried bythe framework of the apparatus,

runner to move down and come in contact with the glass. As the grindingprogresses the handwheel 45 is turned to allow the connecting rod d2 tomove up, thus reducing the compression of the spring and allowing moreandmore of the weight of the runner to press upon the glass. It will beseen that the spring in this construction performs precisely thefunction of the compressed air in the construction .of Figs. 1 and 3,that is, the spring applies a yielding resistance to the downwardmovement of the runner, and

. such resistance increases as the downward movement progresses. Thetendency of the runner to move down suddenly and fracture the glass isthus resisted as in the other types of apparatus. It will also be seenthat the adjustment of the yielding resistance by meansof the handwheel45 corresponds in function to the adjustment secured by the valves inthe constructions of Figs. 1 and 3, as such valves control the,compression of the, air by ,the water, and the air is the equivalent ofthe spring.

In the modification illustrated in Fig. 9, .1 is the table, 2 ,is therunner, 5 is the sup- :porting post, 38 is the lever for supporting andoperating the runners, and 33 is the fulcrum bracket for the lever 38*.The supporting-post 5 is preferably of the type shownin Fig. 2, and isrotatedto secure the tilting. adjustment of the runners by means ofthenhandwheel 11 conn'ecting with-the post5 bymeans of gearingcorresponding tothat in Figs. 1 and The upper end of the post ,keyed toa thrust bearing member 36 -'whose flange is supported by theropposingthrust bearing member 37 antifriction balls being interposedbetween the thrust surfaces. The thrust bearing memher-"37 v isconnected to 'the lever 38 by means of thelink .50, while the other endof the lever 38 is connected to a connecting rod llisimilar to that ofFig. 7 and working in a cylinder 43'? with a spring 44 there- ,insimilar to, the corresponding parts in Fig. 7.1 The cylinder 43 ispivoted at-rts lower .Qlld 'tlO 2lllOtl1Ql' .,CQIlIl8Ctlng rod 42 suchrod constituting-the piston rod for the PlStOn 51 working, in thehydraulic cylinder. 52. The

and movements of. the piston 51 are controlled by means of a three-wayvalve connected to the pipe' 54 lea ding to the upper side of thepiston. Thecylinder and piston 51.52 .con'stiitutea means for regulatingthe tensioniof the spring H, such parts taking the place of the nut andscrew connection n Fig. 7, foiyadjusiing the position of the connee tingrod The actuation of the threeway valve in the pipe olqconstitutes acon- 7 venient means for adjusting the position of the piston 51,and-aside from thevfa ct that this valve is operated instead of thehand- Limst wheel 45, the operation of the apparatus is the same asheretofore described in connection'with Fig. 7.. I

\Vhat- I claim is 1. In apparatus for grinding, a rotating table forcarrying the member to beground,

a runner mounted above the table,'resilient during the grindingoperation, and means for varying the force exerted by the said meansduring the grinding operation.

3. In apparatus for grinding, a rotating table for carrying'the' memberto be ground, a runner mounted above the table, resilient means placedunder stress during the grinding operation and tending to oppose thedownward pressure of the runner due to its weight, and means fordecreasing the stress and permitting more and more of the weight of therunner to be applied to the member as the grinding progresses.

- et. In apparatus for grind-ing,a rotating table for carrying themember to be ground,

a portion of theweight thereof from the member belng gr0und.-

In apparatus for grindin a rotating table for carrying the member to beground,

a runner mounted above the table, yielding movement of the 'iliunner andremoving a 7 portion of the weight thereof from the memher being ground,and means for varying the opposing foreeiexerclsed by the said pneumaticmeans. I

'6. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner mounted above the table, yielding pneumaticmeansopposing-the downward movementof the runner and removing a portionof the weight thereof from the member being ground, and means'forsupplying liquid under pressure for varying the opposing force exercisedby the said pneumatic means.

7 In apparatusfor grinding, a rotating table for carrying the member tobe ground,

a. 'runner mounted above the table, a pneuinatically. operated rain foropposing the downward movement of the runner and removing a. portion ofthe weight thereof from the member being ground, and means for supplyingliquid under pressure to the interior of the ram to compress the gas v105 pneumatic means vopposing the downward therein and increase thelifting power 0 the ram.

In apparatus for grinding, a rotating table for carrying the member tobe ground,

a runner mounted above the table, a post for supporting the runner,resiliently operated means concentric with the post for applying forcethereto tending to lift the runner, and means for varying the forceapplied by the resilient means.

9. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner mounted above the table, a post for supportingthe runner, and a fluid operated lifting ram concentric with the postfor applying force thereto tending to lift the runner.

10. In apparati'is for grinding, a rotating table for carrying themember to be ground, a runner mounted above the table, a post forsupporting the runner, and a-fluid operated lifting device comprising acylinder and piston-concentric with the post with one of said partsfixed against movement and the other secured to the post and adapted toappiy lifting force to the post when fluid is supplied to the interiorof the cylinder.

1.1. In apparatus for grinding, a rotating table for carrying the memberto be ground,

by the device.

12. In apparatus for grinding, a rotating table for'carrying the memberto be ground, a runner mounted above the table, resilient resistancemeans opposing the downward movement of the runner, and fluid pressurecontrolling means for regulating and varying the stress of the saidresilient resistance means.

13. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner above the table, a'post held against rotarymovement with the runner, a supporting thrust bearing carried by thelower end of the post, and an opposing thrust bearing carried by therunner above the said supporting thrust bearing.

14. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner above the table provided at its center with abearing recess, a post held against rotary movement with the runner, abearing block carried detachably upon the lower end of the post and heldagainst rotative and vertical movement with respect to the said post andhaving a thrust bearing surface on its upper face, and a lateral bearingsurface around its periphery opposing the side walls of the said recess,and a' thrust bearing carried by the table above the block and opposingthe bearing surface on the block.

15. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner above the table, a post held against rotarymovement with the runner, a supporting thrust bearing carried by thelower end of the post, an opposing thrust bearing carried by the runnerabove the said supporting thrust bearing, and means whereby the 0st maybe disengaged from the supporting thrust bearing.

16. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner above the table, a post held against rotarymovement with the runner, lateral and thrust bearings carried at thecentral portion of the runner, and opposing lateral and thrust bearingscarried by the lower end of the said post,

1 7. In apparatus for grinding, a rotating table for carrying the memberto be ground, a vertical post supported above the table and held againstlateral and rotary movement, a runner swiveled upon the lower end of thepost, and means for raising and lowering the post and the runner carriedthereby.

l8.- In apparatus for grinding, a rotating table for carrying the memberto be ground, a vertical post supported above the table and held againstlateral and rotary movement, a runner swiveled upon the lower end of thepost, and power means intermediate the ends of the post for moving itvertically.

19. In apparatus for grinding, a rotating table for carrying the memberto be ground, a vertical post supported above the table and held againstlateral and rotary movement, a runner swiveled upon thelower end of thepost, and a fluid operated ram having its piston and cylinder concentricwith the post for raising such post and the runner carried thereby.

'20. In apparatus for grinding, a rotating table for carrying the memberto be ground, a vertical post suspended above the table and held againstlateral and rotary movement, a runner above the table, a lateral andthrust bearing block supported by the lower end of the post off centerwith respect to the center line of the post and nonrotatablewith respectto the post, lateral and thrustbearings carried by the runner inopposition to the lateral and thrust bearings of the block, and meanswhereby the post may be adjusted rotarily about the center line.

21. In apparatus for grinding, a rotating table for carrying the memberto be ground, a vertical post suspended above thettable and held againstlateral and rotary movement, a runner above the table, a bearing blockonwhich the runner is swiveled concentrically, a supporting connectionbetween the post and block off center with respect to the axis ofrotation of the block, and means whereby the post may be adjustedrotarily.

22. In apparatus for grinding, a rotating table for carrying the memberto be ground,

a runner above the table, means forsuspending the runner off centercausing a tendency to tilt, and meansfor adjusting the off center pointof support rotarily about the axis of rotation of the runner.

23. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner above the table, a block upon which the runner isswiveled provided with a vertical recess and with another recessextending laterally from said vertical recess, a post having its lowerend engaging the recess and partially filling it with aprojection'engaging the lateral recess, and a vertically movable keyslidable along the post and fitting into the space in the verticalrecess alongside the end of the post.

24. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner above the table, a block upon which the runner isswiveled provided with a vertical recess and with anotherrecess-extending laterally from said vertical recess, a post supportedintermediate its ends and with its lower end engaging and partiallyfilling the vertical recess and provided with a projection engaging thelateral recess, and a vertically movable key extending longitudinally ofthe post and operable from the upper end thereof and fitting at itslower end into the space in the vertical recess alongside the end of thepost.

25. In apparatus for grinding, a rotating table for carrying the memberto be ground, a runner above the table, a block upon. which the runneris swiveled provided with a vertical recess, a non-rotatable post sup-;ported from above and having its lower end engaging the said recessnon-rotatably, inter-engaging means carried by the lower end of the postand the block whereby the block and runner are held against downwardmovement with respect to the post after the said means are interengaged,and a locking device for locking the post against movement tending todisengage the said means.

of the runner toward and fromthe table, a closed receptacle carrying allqu d and havlng an air chamber, a connection for supfplying liquidfrom the receptacle-to the ram,

pressure to the receptacle to vary the air pressure in the said airchamber.

28. In apparatus for grinding, a rotating table for carrying the memberto beground, a lifting ram for regulating the movements of the runnertoward and from the table, a closed receptacle carrying a liquid andhaving an air chamber, a throttling connection between the ram and thereceptacle for conveying liquid to and from the ram and arranged topermit a relatively free flow of liquid to the ram but to throttle thefluid as it returns to the receptacle, and means for supplying liquidunder pressure to the receptacle to vary the air pressure in the saidair chamber. I

29. In apparatus for grinding, a rotating table for carrying the memberto be ground,

for supplying liquid from the receptacle to the ram, a throttling valvetherein, a bypass with a check valve permitting liquid to pass the valvein its movement to the ram, but preventing the reverse movement throughthe bypass, and means for supplying liquid under pressure to thereceptacle to vary the air pressure in the said air chamber. I

In testimony whereof I have hereunto signed my name in the presence ofthe two subscribed Witnesses.

HALBERT K. HITCHCOCK. \Vitnesses:

Anonwon'rn MARTIN, LETI'TIA A. MYERS.

